Jealousy

Here's one suggested by a friend. Thanks, friend (you know who you are)!

This friend related to me that he once met one of his girlfriend's friends who seemed to hit on him. His girlfriend was there and noticed the overtures as well and was not appreciative.

This made me think about different gender reactions to these scenarios. Do you think this is true?

Scenario 1
A guy's friends tell him his girlfriend is hot. His response, "Hell yeah!"

Scenario 2
A girl's friends tell her that her boyfriend is hot. Her response, "Stay away!"

Scenario 3
A strange guy tries hitting on another guy's girlfriend. Stranger punched in jaw.

Scenario 4
A strange girl tries hitting on another girl's boyfriend. "No worries, he's all mine."

Are these realistic reactions?